yah, i've heard something like that before. competition wasn't the only factor, but it was a meaningful contributor. the tokyo operators compete on service and amenities (differentiation strategy), which is what allowed them to find profitable niches beyond just ticket sales (complementary/flanking offerings), and buoys the marketplace itself.

in capital intensive infrastructure businesses like rail travel and telecom, it actually makes sense for the government to provide the high upfront capital to build the common infrastructure and lease it to the competitors (but not sell or give it away) to create viable markets like this.